A conventional semiconductor device has a semiconductor element, which is a heat generating component, mounted thereon. The semiconductor element generates heat when the semiconductor device is driven. To improve dissipation of this heat, a thick metal substrate or ceramic substrate provided with a circuit pattern is used. In addition, to increase a heat dissipation area to improve the heat dissipation, a fin base including heat dissipation fins is screwed and joined to the metal substrate with an insulative silicone-based resin material such as grease interposed therebetween, for example.
A semiconductor device thus configured, however, requires a step of applying the silicone-based resin material to a surface of the metal substrate or ceramic substrate or of a heat dissipation member, resulting in an increased number of manufacturing steps. Furthermore, heat dissipation properties deteriorate due to the silicone-based resin material interposed between the metal substrate or ceramic substrate and the fin base.
Therefore, as a technique that does not include the resin material interposed as described above, for example, there has been proposed a semiconductor device which includes a ceramic substrate mounted on a metal plate with fins, and which is entirely sealed with epoxy resin (for example, PTD 1 and PTD 2).